It is expected that Middle box like Network Address Translator (NAT) or Firewall or Proxy or ALG will not go away completely at least in near future. This box is going to exist in wireless networks due to a variety of reasons. For example, a wireless network provider would not like to expose the private addresses used in its network to the outside world. Similar problem also occurs, when a mobile user moves from a Wireless LAN (WLAN) environment (Office) to cellular network environment (Outside). Equipment's that provide services to the customers may include cache servers, proxy servers, content servers and load balancers. These equipments operate in private address space in a network provider's routing premise. This imposes a problem when the mobile user moves to the adjacent domain causing a hand-off. Currently standards are mainly looking into the issues of fast hand-offs and context transfer between access routers from one domain to another. The task of relocating context when the mobile node moves from one private address space to other private address space creates a problem especially when the mobile node has session with cache/content server which is in private address space of network provider.
NAT, Firewall, Multimedia buffers, Signature Management for Intrusion detection system are all considered to be Middle box and are deployed widely in the enterprise and expected to grow. As trusted third parties are increasingly being asked to make policy decisions on behalf of the various entities participating in an application's operation, a need has developed for applications to be able to communicate their needs to the devices in the network that provide transport policy enforcement.
Wireless network providers would like to use site-local private addresses in their networks. This creates a problem when the mobile node is connected to a content server and is downloading some data and hand-off occurs. It may be a good strategy to restart the session for certain applications but this strategy would not work for real-time interactive applications like gaming.
The above-mentioned references are exemplary only and are not meant to be limiting in respect to the resources and/or technologies available to those skilled in the art.